1. Field of the Invention
The present invention relates to a liquid transporting apparatus which transport a liquid and a method for producing a liquid transporting apparatus.
2. Description of Related Art
As an example of conventional recording apparatus which performs recording on a recording medium such as paper, an ink-jet printer provided with an ink-jet head is known (for example, see Patent Document 1).
[Patent Document 1] Japanese Patent Publication No. 3128857
As shown in FIG. 47, the ink-jet head 420 is constructed of a stack in which an actuator plate 421 driven by a drive voltage generated in a driving circuit (not shown), a cavity plate 422 forming an ink channel for flowing an ink threrethrough, and a nozzle plate 423 provided with nozzles 424 from which the ink is ejected are stacked in layers such that the piezoelectric actuator plate 421, the cavity plate 422 and the nozzle plate 423 are positioned at upper, middle and lower portions in the stack respectively. The cavity plate 422 is constructed of three layers 422a to 422c stacked on top of the each other. With the etching or the like, pressure chambers 430 for accommodating the ink are formed in the upper layer 422a, a manifold (now shown) for supplying the ink to the pressure chambers and communicating holes 432 are formed in the lower layer 422c, and communicating holes (now shown) for communicating the pressure chambers 430 and the manifold and communicating holes 431 for communicating the pressure chambers 430 and the nozzles 424 are formed in the middle layer 422b. 
The piezoelectric actuator plate 421 is formed of a piezoelectric ceramic material made of a lead zirconate titanate (PZT) of ceramic material, and is provided with a plurality of piezoelectric ceramics layers 440 having the piezoelectric effect and a plurality of inner-side electrodes 445, 446, 447, 448, 449, 450 interposed between the ceramic layers. Each of the inner-side electrodes 445 to 450 is arranged in a portion corresponding to the central portion of one of the pressure chambers 430. The portions of the piezoelectric ceramic layers 440, sandwiched between the inner-side electrodes 445 to 450, serve as active portions 445, 456, 457, 458, 459 each of which extends in a direction in which the layers are stacked when a voltage is applied to the inner-side electrodes 445 to 450. As shown in FIG. 48, when a voltage is applied to the inner-side electrodes 445 to 450, in the piezoelectric actuator plate 421, which correspond to an arbitrary pressure chamber 430a, an electric field parallel to the polarization direction is generated in the active portion 455 to 459, then the active portions 455 to 459 extend in the direction in which the layers are stacked so that pressure is applied to the ink in the pressure chamber 430 for ejecting the ink.
However, as shown in FIG. 48, in the conventional technique as described above, the electrodes 445 to 450 are formed to substantially match the shape of the pressure chamber 430 in a plan view and the electrodes 455 to 450 are stacked on top of each other. Accordingly, there is an increase in the surface area of the portions of the piezoelectric ceramic layers 440 disposed between the electrodes 445 to 450, which give rise to problems such that a capacitance is increased, a larger electric current is required in order to rapidly drive the piezoelectric actuator, which in turn decreases the energy efficiency in the piezoelectric actuator.
In addition, when the active portions 455 to 459 deform to project downwardly toward a certain pressure chamber 430a for performing the ejection of the ink, the downward deformation of the active portions 445 to 459 produces an opposite reaction, which in turn causes a portion of the piezoelectric actuator plate 421 disposed above another pressure chamber 430a adjacent to the certain pressure chamber 430a to bend to project upwardly, with a portion above a partition wall 430c between these pressure chambers 430 (430a and 430b) functioning as a fulcrum P1. In addition, the opposite reaction applies force to the partition wall 430c so that the partition wall 430c tilts toward the pressure chamber 430a. In this way, the operation for electing ink from an arbitrary pressure chamber 430a also changes the volume in another pressure chamber 430b adjacent to the arbitrary pressure chamber 430a, which in turn causes the change in pressure in the ink in the adjacent pressure chamber 430b. When the ink is ejected from the adjacent pressure chamber 430b, there arises a problem of so-called cross talk in some cases in which the velocity and the volume of ejected ink droplets become varied or non-uniform, thereby lowering the printing quality of the ink-jet head 420.